Death Valley geology field trip

Ubehebe Crater

Over a dozen volcanoes dot the landscape of Ubehebe volcanic field. Ubehebe Crater is the largest and youngest volcanic feature, Little Hebe crater is at lower right. Photo by Peter Sanchez, NPS

At the edge of Ubehebe Crater, you'll be greeted by an eerie, surreal
landscape. All is quiet now, but imagine yourself transported to a time
just over two thousand years ago...

...Following weaknesses in the Earth's crust, searing
basaltic magma rose upward. A fault along the western
base of Tin Mountain, responsible for uplift of the entire Cottonwood
mountain range, lay in
the path of the molten mass, providing an easy
escape route to the surface. Breaking through the bedrock below, black
lava races through the gravely
alluvial fan draped across the valley floor.

Fire and water

Magma worked its way through the fault-weakened rock toward the
surface. Some of Ubehebe Crater field's most dramatic
eruptions occurred when magma met water-soaked
bedrock and alluvial fan sediments. In
an instant,
water flashed to steam, and a violent release of
steam-powered energy blasted away the confining
rock above. (This is called a hydrovolcanic eruption.)
It produced a dense, ground-hugging cloud of rocky
debris which surged out from the base at up to
100 miles/hour, decimating the landscape.
A fiery fountain of lava erupted with a roar, forming
a vent to the south of what is now Ubehebe Crater. Liquid
rock was thrown
into the air, then fell to the ground as solidified
cinders or partially-molten lava blocks and bombs.
A ring of black volcanic material soon builds around
the central vent. The first of the Ubehebe Crater
complex is born.

A look into the depths of Ubehebe Crater, the largest and youngest volcanic feature at this stop. The eruptions that created Ubehebe Crater blasted through older conglomerate layers, now revealed in the crater walls. Photo by W.R. Jones, NPS.

The largest of these eruptions produced Ubehebe Crater, over a half a mile
wide and 770 feet deep. Up to 150 feet of rock debris mantles the countryside
near the site of the explosion.

Over a dozen other explosion craters and tuff rings in
the Ubehebe Crater field are the result of this type
of hydrovolcanic eruption.